Assessing the impact of knowledge management strategies announcements on the market value of firms

Although there is much literature on the relationship between KM strategies and organizational performance, the benefit of KM strategies is not well understood. We addressed this issue by exploring how KM strategies influence a firm's market value using event study methodology. We evaluated the cumulative abnormal returns for KM strategies announced by U. S. firms from 1998 to 2003. Our findings supported the hypothesis that firms’ announcements about their KM strategies provoked positive reactions in the market. More specifically, strategies that focus on either (i) knowledge reusability through IT or (ii) knowledge sharing through informal discussions among employees contributed to higher performance than strategies that emphasized both. This outcome empirically supported our argument that the emphasis on either tacit or explicit knowledge results in a better market value of the firm. Furthermore, the market's reaction to the announcement is dependent on the firm's industry classification. The findings of this study offer insights that may help managers maximize the market impact of their KM strategies.     

Feature selection for manufacturing process monitoring using cross-validation

A novel algorithm is developed for feature selection and parameter tuning in quality monitoring of manufacturing processes using cross-validation. Due to the recent development in sensing technology, many on-line signals are collected for manufacturing process monitoring and feature extraction is then performed to extract critical features related to product/process quality. However, lack of precise process knowledge may result in many irrelevant or redundant features. Therefore, a systematic procedure is needed to select a parsimonious set of features which provide sufficient information for process monitoring. In this study, a new method for selecting features and tuning SPC limits is proposed by applying k-fold cross-validation to simultaneously select important features and set the monitoring limits using Type I and Type II errors obtained from cross-validation. The monitoring performance for production data collected from ultrasonic metal welding of batteries demonstrates that the proposed algorithm is able to select the most efficient features and control limits and thus leading to satisfactory monitoring performance.     

The impact of information technology on financial performance: the importance of strategic choice

Information technology (IT) may not automatically improve firm profitability. It is an essential tool, but not sufficient in itself, and should therefore be coupled with organisational factors such as business strategies. A firm can maximise the value from its IT investments by aligning them with business strategies because IT improves scope economies and coordination. This paper examines empirically the contribution of IT to financial performance as measured by net profit, ROA, and ROE by focusing on the alignment of IT with business strategies such as vertical disintegration and diversification. Empirical analysis shows that IT does not directly improve financial performance. In conjunction with vertical disintegration and diversification, however, it does improve financial performance as measured by net profit. Financial performance ratios such as ROA and ROE, however, are not correlated with the alignment (or interaction) factor of IT with vertical disintegration and diversification. The results indicate that increased IT spending improves net profit, but not performance ratios such as ROA and ROE, of firms with decreased vertical integration and higher diversification.     

Evolutionary strategies for hyperparameters of support vector machines based on multi-scale radial basis function kernels

Kernel functions are used in support vector machines (SVM) to compute inner product in a higher dimensional feature space. SVM classification performance depends on the chosen kernel. The radial basis function (RBF) kernel is a distance-based kernel that has been successfully applied in many tasks. This paper focuses on improving the accuracy of SVM by proposing a non-linear combination of multiple RBF kernels to obtain more flexible kernel functions. Multi-scale RBF kernels are weighted and combined. The proposed kernel allows better discrimination in the feature space. This new kernel is proved to be a Mercer’s kernel. Furthermore, evolutionary strategies (ESs) are used for adjusting the hyperparameters of SVM. Training accuracy, the bound of generalization error, and subset cross-validation on training accuracy are considered to be objective functions in the evolutionary process. The experimental results show that the accuracy of multi-scale RBF kernels is better than that of a single RBF kernel. Moreover, the subset cross-validation on training accuracy is more suitable and it yields the good results on benchmark datasets.     

A new supervised classification algorithm in artificial immune systems with its application to carotid artery Doppler signals to diagnose atherosclerosis

Because of its self-regulating nature, immune system has been an inspiration source for usually unsupervised learning methods in classification applications of Artificial Immune Systems (AIS). But classification with supervision can bring some advantages to AIS like other classification systems. Indeed, there have been some studies, which have obtained reasonable results and include supervision in this branch of AIS. In this study, we have proposed a new supervised AIS named as Supervised Affinity Maturation Algorithm (SAMA) and have presented its performance results through applying it to diagnose atherosclerosis using carotid artery Doppler signals as a real-world medical classification problem. We have employed the maximum envelope of the carotid artery Doppler sonograms derived from Autoregressive (AR) method as an input of proposed classification system and reached a maximum average classification accuracy of 98.93% with 10-fold cross-validation method used in training-test portioning. To evaluate this result, comparison was done with Artificial Neural Networks and Decision Trees. Our system was found to be comparable with those systems, which are used effectively in literature with respect to classification accuracy and classification time. Effects of system's parameters were also analyzed in performance evaluation applications. With this study and other possible contributions to AIS, classification algorithms with effective performances can be developed and potential of AIS in classification can be further revealed.     

基于典型相关分析的多视图跨领域情感分类

跨领域的文本分类,是指利用有标记领域的知识去帮助另一个概率分布不同的,未标记领域的知识进行分类的问题。从多视图学习的视角提出一个新的跨领域文本分类的方法(MTV算法)。通过在核空间典型相关分析中引入与标记相关的信息,MTV算法可以得到一个判别性能更优的公共子空间。在多个情感类文本数据上的实验表明,MTV算法可以大大提升传统监督式学习算法面对领域迁移时的分类性能,并且在引入判别式的核空间典型相关分析后,进一步优化性能。     

The use of data mining and neural networks for forecasting stock market returns

It has been widely accepted by many studies that non-linearity exists in the financial markets and that neural networks can be effectively used to uncover this relationship. Unfortunately, many of these studies fail to consider alternative forecasting techniques, the relevance of input variables, or the performance of the models when using different trading strategies. This paper introduces an information gain technique used in machine learning for data mining to evaluate the predictive relationships of numerous financial and economic variables. Neural network models for level estimation and classification are then examined for their ability to provide an effective forecast of future values. A cross-validation technique is also employed to improve the generalization ability of several models. The results show that the trading strategies guided by the classification models generate higher risk-adjusted profits than the buy-and-hold strategy, as well as those guided by the level-estimation based forecasts of the neural network and linear regression models.     

Using Correspondence Analysis to Combine Classifiers

Several effective methods have been developed recently for improving predictive performance by generating and combining multiple learned models. The general approach is to create a set of learned models either by applying an algorithm repeatedly to different versions of the training data, or by applying different learning algorithms to the same data. The predictions of the models are then combined according to a voting scheme. This paper focuses on the task of combining the predictions of a set of learned models. The method described uses the strategies of stacking and Correspondence Analysis to model the relationship between the learning examples and their classification by a collection of learned models. A nearest neighbor method is then applied within the resulting representation to classify previously unseen examples. The new algorithm does not perform worse than, and frequently performs significantly better than other combining techniques on a suite of data sets.     

An extensive analysis of the interaction between missing data types,imputation methods,and supervised classifiers

When applying data-mining techniques to real-world data, we often find ourselves facing observations that have no value recorded for some attributes. This can be caused by several phenomena, such as a machine’s incapability to record certain characteristics or a person refusing to answer a question in a poll. Depending on that motivation, values gone missing may follow one kind of pattern or another, or describe no regularity at all. One approach to palliate the effect of missing data on machine learning tasks is to replace the missing observations. Imputation algorithms attempt to calculate a value for a missing gap, using information associated with it, i.e., the attribute and/or other values in the same observation. While several imputation methods have been proposed in the literature, few works have addressed the question of the relationship between the type of missing data, the choice of the imputation method, and the effectiveness of classification algorithms that used the imputed data. In this paper we address the relationship among these three factors. By constructing a benchmark of hundreds of databases containing different types of missing data, and applying several imputation methods and classification algorithms, we empirically show that an interaction between imputation methods and supervised classification can be deduced. Besides, differences in terms of classification performance for the same imputation method in different missing data patterns have been found. This points to the convenience of considering the combined choice of the imputation method and the classifier algorithm according to the missing data type.     

An experimental comparison of cross-validation techniques for estimating the area under the ROC curve

Reliable estimation of the classification performance of inferred predictive models is difficult when working with small data sets. Cross-validation is in this case a typical strategy for estimating the performance. However, many standard approaches to cross-validation suffer from extensive bias or variance when the area under the ROC curve (AUC) is used as the performance measure. This issue is explored through an extensive simulation study. Leave-pair-out cross-validation is proposed for conditional AUC-estimation, as it is almost unbiased, and its deviation variance is as low as that of the best alternative approaches. When using regularized least-squares based learners, efficient algorithms exist for calculating the leave-pair-out cross-validation estimate.     

最小二乘支持向量机在医疗数据分析中的应用

以医疗数据为应用对象,应用网格搜索和交叉验证的方法选择参数,建立最小二乘支持向量机分类器,进行实际验证,并与使用K近邻分类器(K-NN)和C4.5决策树两种方法的结果进行比较.结果表明,LS-SVM分类器取得较高的准确率,表明最小二乘支持向量机在医疗诊断研究中具有很大的应用潜力.     

Hybrid dendritic computing with kernel-LICA applied to Alzheimer's disease detection in MRI

Dendritic computing has been proved to produce perfect approximation of any data distribution. This result guarantees perfect accuracy training. However, we have found great performance degradation when tested on conventional k-fold cross-validation schemes. In this paper we propose to use Lattice Independent Component Analysis (LICA) and the Kernel transformation of the data as an appropriate feature extraction that improves the generalization of dendritic computing classifiers. We obtain a big increase in classification performance applying with this schema over a database of features extracted from Magnetic Resonance Imaging (MRI) including Alzheimer's disease (AD) patients and control subjects.     

Top-down learning strategies: can they facilitate stylus keyboard learning?

Learning a new stylus keyboard layout is time-consuming yet potentially rewarding, as optimized virtual keyboards can substantially increase performance for expert users. This paper explores whether the learning curve can be accelerated using top-down learning strategies. In an experiment, one group of participants learned a stylus keyboard layout with top-down methods, such as visuo-spatial grouping of letters and mnemonic techniques, to build familiarity with a stylus keyboard. The other (control) group learned the keyboard by typing sentences. The top-down learning group liked the stylus keyboard better and perceived it to be more effective than the control group. They also had better memory recall performance. Typing performance after the top-down learning process was faster than the initial performance of the control group, but not different from the performance of the control group after they had spent an equivalent amount of time typing. Therefore, top-down learning strategies improved the explicit recall as expected, but the improved memory of the keyboard did not result in quicker typing speeds. These results suggest that quicker acquisition of declarative knowledge does not improve the acquisition speed of procedural knowledge, even during the initial cognitive stage of the virtual keyboard learning. They also suggest that top-down learning strategies can motivate users to learn a new keyboard more than repetitive rehearsal, without any loss in typing performance.     

Effects of feature construction on classification performance: An empirical study in bank failure prediction

While extensive research in data mining has been devoted to developing better classification algorithms, relatively little research has been conducted to examine the effects of feature construction, guided by domain knowledge, on classification performance. However, in many application domains, domain knowledge can be used to construct higher-level features to potentially improve performance. For example, past research and regulatory practice in early warning of bank failures has resulted in various explanatory variables, in the form of financial ratios, that are constructed based on bank accounting variables and are believed to be more effective than the original variables in identifying potential problem banks. In this study, we empirically compare the performance of two sets of classifiers for bank failure prediction, one built using raw accounting variables and the other built using constructed financial ratios. Four popular data mining methods are used to learn the classifiers: logistic regression, decision tree, neural network, and k-nearest neighbor. We evaluate the classifiers on the basis of expected misclassification cost under a wide range of possible settings. The results of the study strongly indicate that feature construction, guided by domain knowledge, significantly improves classifier performance and that the degree of improvement varies significantly across the methods.     

Efficient pattern synthesis for nearest neighbour classifier

Synthetic pattern generation is one of the strategies to overcome the curse of dimensionality, but it has its own drawbacks. Most of the synthetic pattern generation techniques take more time than simple classification. In this paper, we propose a new strategy to reduce the time and memory requirements by applying prototyping as an intermediate step in the synthetic pattern generation technique. Results show that through the proposed strategy, classification can be done much faster without compromising much in terms of classification accuracy, in fact for some cases it gives better accuracy in lesser time. The classification time and accuracy can be balanced according to available memory and computing power of a system to get the best possible results.     

Multiple surrogates: how cross-validation errors can help us to obtain the best predictor

Surrogate models are commonly used to replace expensive simulations of engineering problems. Frequently, a single surrogate is chosen based on past experience. This approach has generated a collection of papers comparing the performance of individual surrogates. Previous work has also shown that fitting multiple surrogates and picking one based on cross-validation errors (PRESS in particular) is a good strategy, and that cross-validation errors may also be used to create a weighted surrogate. In this paper, we discussed how PRESS (obtained either from the leave-one-out or from the k-fold strategies) is employed to estimate the RMS error, and whether to use the best PRESS solution or a weighted surrogate when a single surrogate is needed. We also studied the minimization of the integrated square error as a way to compute the weights of the weighted average surrogate. We found that it pays to generate a large set of different surrogates and then use PRESS as a criterion for selection. We found that (1) in general, PRESS is good for filtering out inaccurate surrogates; and (2) with sufficient number of points, PRESS may identify the best surrogate of the set. Hence the use of cross-validation errors for choosing a surrogate and for calculating the weights of weighted surrogates becomes more attractive in high dimensions (when a large number of points is naturally required). However, it appears that the potential gains from using weighted surrogates diminish substantially in high dimensions. We also examined the utility of using all the surrogates for forming the weighted surrogates versus using a subset of the most accurate ones. This decision is shown to depend on the weighting scheme. Finally, we also found that PRESS as obtained through the k-fold strategy successfully estimates the RMSE.     

定向判别分析新算法及应用

本文介绍了多元有序数据定向判别分析新方法的原理、建模流程、应用流程和应用实例。这种判别分析将分类建模与判别归类分开。新方法用多组或逐步判别分析对多元有序数据建模，应用时根据应用领域的知识对样本归属作初步定向，然后选择模型的相关局部进行判别归类。这种方法解决了由于时间序列多元数据周期性造成的样本分类颠倒问
问题。     

Using planning techniques in intelligent tutoring systems

This paper proposes an architecture for building better Computer-Assisted Instruction (CAI) programs by applying and extending Artificial Intelligence (AI) techniques which were developed for planning and controlling the actions of robots. A detailed example shows how programs built according to this architecture are able to plan global teaching strategies using local information. Since the student's behavior can never be accurately predicted, the pre-planned teaching strategies may be foiled by sudden surprises and obstacles. In such cases, the planning component of the program is dynamically reinvoked to revise the unsuccessful strategy, often by recognizing student misconceptions and planning a means to correct them. This plan-based teaching strategy scheme makes use of global course knowledge in a flexible way that avoids the rigidity of earlier CAI systems. It also allows larger courses to be built than has been possible in most AI-based “intelligent tutoring systems” (ITSs), which seldom address the problem of global teaching strategies.     

定向判别分析新算法及其在沉积化学中的应用

介绍了处理多元有序数据的定向判别分析新方法原理、建模流程、应用流程及其在沉积化学中的应用实例。这种判别分析将分类建模与判别归类分开,求解与专业知识结合。新方法用多组或逐步判别分析对多元有序数据建模,应用时根据应用领域的知识对样本归属作初步定向,然后选择模型的相关局部进行判别归类,从而实现有序判别。这种方法用于解决由于时间序列多元数据周期性造成的样本分类颠倒问题。在塔里木盆地沉积岩时间序列化学数据的应用实例中,解决了石油井下地层预测和归类问题。     

An improved approach to medical data sets classification: artificial immune recognition system with fuzzy resource allocation mechanism

Abstract: The artificial immune recognition system (AIRS) has been shown to be an efficient approach to tackling a variety of problems such as machine learning benchmark problems and medical classification problems. In this study, the resource allocation mechanism of AIRS was replaced with a new one based on fuzzy logic. The new system, named Fuzzy-AIRS, was used as a classifier in the classification of three well-known medical data sets, the Wisconsin breast cancer data set (WBCD), the Pima Indians diabetes data set and the ECG arrhythmia data set. The performance of the Fuzzy-AIRS algorithm was tested for classification accuracy, sensitivity and specificity values, confusion matrix, computation time and receiver operating characteristic curves. Also, the AIRS and Fuzzy-AIRS algorithms were compared with respect to the amount of resources required in the execution of the algorithm. The highest classification accuracy obtained from applying the AIRS and Fuzzy-AIRS algorithms using 10-fold cross-validation was, respectively, 98.53% and 99.00% for classification of WBCD; 79.22% and 84.42% for classification of the Pima Indians diabetes data set; and 100% and 92.86% for classification of the ECG arrhythmia data set. Hence, these results show that Fuzzy-AIRS can be used as an effective classifier for medical problems.